1. Field of the Invention
The present invention relates generally to methods and apparatuses for providing a low voltage high current bi-directional termination voltage regulator. More specifically, the invention relates to methods and apparatuses for providing a voltage regulator suitable for sourcing and sinking a maximum of approximately 1 Amp of current from data lines that make up a stack bus for the purpose of terminating the stack bus to a termination voltage of approximately 2.5V at an impedence of approximately 68.OMEGA.. In one embodiment, the bi-directional termination voltage regulator is used to source and sink current for a termination circuit that terminates a stack bus for a Class II Fast Ethernet repeater stack. The termination circuit is selectively connected to the bus at the repeaters in the repeater stack that happen to be plugged into the top and bottom ends of the stack. The termination circuit prevents reflections of signals on the bus that would otherwise occur and degrade the performance of the bus. The low voltage high current bi-directional termination voltage regulator enables the termination circuit to source and sink large amounts of current while using only a low voltage termination power supply at about 4V from the stack bus connection cable.
2. Description of the Related Art
The growth of local-area networks (LANs) has been driven by the introduction of Ethernet Technology as well as the availability of powerful, affordable personal computers and workstations. As a result, applications that once were possible only on mainframe computers are now running on LANs. Network speed and availability are critical requirements. However, existing applications and a new generation of multimedia, groupware, imaging, and database products can tax a network running at Ethernet's traditional speed of 10 megabits per second (Mbps). Moreover, with more applications requiring faster LAN speeds for acceptable performance, network managers increasingly find that high-performance computation platforms and mission-critical applications can overwhelm a 10 Mbps network. Network managers therefore are increasingly implementing high-speed LAN technology.